Methods for securing an optical fiber to a ferrule and optical connectors formed by such methods

ABSTRACT

A method of securing an optical fiber to a ferrule includes disposing an adhesive composition in a fiber-receiving passage of the ferrule to form a ferrule adhesion system. The adhesive composition in the ferrule adhesion system comprises a polymeric material in a solid form. The method also involves assembling an optical connector with the ferrule adhesion system, heating the ferrule in the optical connector to melt the adhesive composition, and inserting the optical fiber into the fiber-receiving passage of the ferrule and into contact with the adhesive composition that has been melted. The adhesive composition bonds the optical fiber to an inner surface of the ferrule upon cooling and solidifying.

RELATED APPLICATIONS

This application is a continuation of 15/358,434, filed on Nov. 22,2016, which is a continuation of U.S. Pat. No, 9,568,686, filed on Jan.13, 2014, which is a continuation of International Application No.PCT/US13/64007, filed on Oct. 9, 2013, which claims the benefit ofpriority of: U.S. Pat. No. 8,696,215, filed on Mar. 13, 2013; U.S. Pat.No. 9,039,295, filed on Mar. 5, 2013; U.S. Provisional ApplicationSerial No. 61/713,788, filed on Oct. 15, 2012; and U.S. ProvisionalApplication Ser. No. 61/713,779, filed on Oct. 15, 2012. The contents ofall of these patents and applications are relied upon and incorporatedherein by reference.

BACKGROUND Field

The present disclosure generally relates to materials and methods foradhering parts within optical connectors, and more specifically tooptical connectors and ferrule adhesion systems including adhesivecompositions for adhering optical fibers to ferrules, and relatedmethods.

Technical Background

In the assembly of optical connectors, adhesives may be, used to bondoptical fibers to ferrules. The adhesives may typically be thermosetresins, such as epoxies. The present inventors have recognized that aneed exists for an optical fiber adhesive with enhanced bondingproperties,

BRIEF SUMMARY

One embodiment of this disclosure relates to a method for securing anoptical fiber to a ferrule. The method involves disposing an adhesivecomposition in a fiber-receiving passage of the ferrule to form aferrule adhesion system, wherein the adhesive composition in the ferruleadhesion system comprises a polymeric material in a solid form. Themethod also involves: assembling an optical connector with the ferruleadhesion system, wherein the optical connector includes a connectorhousing in which the ferrule is at least partially disposed; heating theferrule in the optical connector to melt the adhesive composition; andinserting the optical fiber into the fiber-receiving passage of theferrule and into contact with the adhesive composition that has beenmelted. The adhesive composition bonds the optical fiber to an innersurface of the ferrule upon cooling and solidifying.

According to another embodiment of this disclosure, a method of securingan optical fiber to a ferrule involves disposing an adhesive compositionin a fiber-receiving passage of the ferrule to form a ferrule adhesionsystem, wherein the adhesive composition comprises a polymeric materialin a solid form. The method also involves: storing the adhesivecomposition. In the solid form, in the fiber-receiving passage of theferrule for at least 8 hours; heating the ferrule to melt the adhesivecomposition after the storing step; and inserting the optical fiber intothe fiber-receiving passage of the ferrule and into contact with theadhesive composition that has been melted, wherein the adhesivecomposition bonds the optical fiber to an inner surface of the ferruleupon cooling and solidifying.

Additional features and advantages of the technology disclosed hereinwill be set forth in the detailed description which follows, and in partwill be readily apparent to those skilled in the art from thatdescription or recognized by practicing the technology as describedherein, including the, detailed description which follows, the claims,as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description present embodiments of thetechnology, and are intended to provide an overview or framework forunderstanding the nature and character of the technology as it isclaimed. The accompanying drawings are included to provide a furtherunderstanding of the technology, and are incorporated into andconstitute a part of this specification. The drawings illustrate variousembodiments and together with the description serve to explain theprinciples and operations of the technology. Additionally, the drawingsand descriptions are meant to be merely illustrative, and are n intendedto limit the scope of the claims in any manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of specific embodiments of thepresent disclosure can be best understood when read in conjunction withthe following drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 is a lengthwise cross-sectional view of a fiber optic mechanicalsplice connector to be mounted on an end portion of a field opticalfiber; and

FIG. 2 illustrates a fiber-receiving passage of a connector ferrule.

FIG. 3 is, a perspective view of a ferrule according to anotherexemplary embodiment

FIG. 4 is a lengthwise cross-sectional view of a connector according toanother exemplary embodiment.

DETAILED DESCRIPTION

Reference will now be made in greater detail to various embodiments,some embodiments of which are illustrated in the accompanying drawings.Whenever possible, the same reference numerals will be used throughoutthe drawings to refer to the same or similar parts. Generally, disclosedherein are various embodiments of adhesive compositions for use inadhering optical fibers to ferrules within optical connectors, and themethods for use thereof. The various embodiments of adhesivecompositions described herein may provide desirable properties, such as,but not limited to, high adhesion strength and/or improved performancefollowing environmental aging. Various embodiments of the adhesivecompositions disclosed herein may also have other desirable propertiesfor the process of securing an optical fiber within a ferrule, such as,but not limited to, shortened process cycle time, no required mixing,and/or no potlife issues.

Referring to FIG. 1, a field-installable, mechanical splice fiber opticconnector 10 suitable for use with the present technology is shown. Thefiber optic connector 10 may include features similar to those of amember of the UNICAM® family of mechanical splice connectors availablefrom Corning Cable Systems, LLC of Hickory, N.C. While one embodiment ofa fiber optic connector is depicted in FIG. 1, it should be understoodthat the adhesive compositions and methods for adhering a glass fiber toa ferrule as described herein are applicable to any fiber opticconnector of any design. Such fiber optic connectors include, but arenot limited to, single-fiber (see, e.g., ferrule 12 of connectors 10,10′ as shown in FIGS. 1 and 4) or multi-fiber (see, e.g., ferrule 12′ asshown in FIG. 3) connectors, such as fusion splice or mechanical spliceconnectors. Examples of typical single fiber mechanical spliceconnectors are provided in U.S. Pat. Nos. 4,755,018; 4,923,274;5,040,867; and 5,394,496. Examples of typical multi-fiber mechanicalsplice connectors are provided in U.S. Pat. Nos. 6,173,097; 6,379,054;6,439,780; and 6,816,661.

As is illustrated with further reference to FIG. 2, the mechanicalsplice connector 10 includes a connector ferrule 12 defining alengthwise, longitudinal bore, referred to herein as a fiber-receivingpassage 30. The fiber-receiving passage 30, which is illustrated inexaggerated scale in FIG. 2, defines an inner surface of the ferrule 12,which may be contacted with an adhesive composition 40 to secure anoptical fiber, such as a stub optical fiber 14. The adhesive composition40 may be disposed within the ferrule 12 and in contact with the innersurface of the ferrule 12 and the stub optical fiber 14. Variousembodiments of the adhesive composition 40, including variations ofadhesive compositions are described in detail herein. In variousembodiments, the adhesive composition 40 may generally comprise apartially cross-linked resin and a coupling agent, as is described indetail herein.

The ferrule 12 may typically comprise a ceramic material, such as, butnot limited to, zirconia, alumina, titanium-doped alumina, glass-filledPPS, or combinations thereof. However, other materials of constructionof the ferrule are contemplated herein, such as metals, ceramics,polymers, or combinations thereof.

The stub optical fiber 14 may be a flexible, transparent optical fibermade of glass or plastic. It may function as a waveguide to transmitlight between the two ends of the optical fiber. Optical fiberstypically include a transparent core surrounded by a transparentcladding material with a lower index of refraction. Light may be kept inthe core by total internal reflection. Glass optical fibers may comprisesilica, but some other materials, such as fluorozirconate,fluoroaluminate, and chalcogenide glasses, as well as crystallinematerials, such as sapphire, may be used. Although shown as the stubfiber 14 in FIG. 1, in other embodiments optical fibers that are notstub fibers may be included and used in combination with the ferrule 12,12′ and processes disclosed herein.

The light may be guided down the core of the optical fiber 14 by anoptical cladding with a lower refractive index that traps light in thecore through total internal reflection, The cladding may be coated by abuffer and/or another coating(s) that protects it from moisture and/orphysical damage. These coatings may be UV-cured urethane acrylatecomposite materials applied to the outside of the optical fiber 14during the drawing process. The coatings may protect the strands ofglass fiber. The optical fiber 14 may comprise an inner primary coatingand an outer secondary coating. Optical fiber coatings may be applied inconcentric layers.

Still referring to FIG. 1, the forward end (also referred to herein asthe end face) 11 of the ferrule 12 is typically precision polished suchthat the stub optical fiber 14 is flush with (as shown) or slightlyprotruding from the end face of the ferrule 12. However, the stuboptical fiber 14 may also protrude outwardly from the end face 11 of theferrule 12 a predetermined distance, if desired. Furthermore, the endface 11 may be oriented generally perpendicular to the optical fiberreceiving passage to provide an Ultra Physical Contact (UPC) typeconnector, or may be formed at a predetermined angle to provide anAngled Physical Contact (APC) type connector, in a known manner. Inaddition, although a single fiber ferrule 12 is shown for purposes ofconvenience, the ferrule 12 may define a plurality of lengthwise opticalfiber receiving passages therethrough for receiving a correspondingplurality of stub optical fibers to provide a multi-fiber mechanicalsplice connector or other multi-fiber connector (see generallymulti-fiber ferrule 12′ as shown in FIG. 3 for a multi-fiber connector).

Generally, the rear end 13 of the ferrule 12 is inserted into andsecured within the forward end of a ferrule holder 16 so that the stuboptical fiber 14 extends rearwardly a predetermined distance from theferrule between a pair of opposed splice components 17, 18, disposedwithin the ferrule holder. In turn, the ferrule holder 16, including theferrule 12 and splice components 17, 18 is disposed within a connectorhousing 19. A cam member 20 is movably mounted between the ferruleholder 16 and the connector housing 19 for engaging a keel portion ofthe lower splice component 18, as will be described. If desired, theferrule 12, the ferrule holder 16 and the cam member 20 may be biasedrelative to the connector housing 19, for example by a coil spring 21,to ensure physical contact between the end face 11 of the ferrule 12 andthe end face of an opposing ferrule in a mating fiber optic connector oroptical device. Finally, a spring retainer 22 may be disposed betweenthe connector housing 19 and a medial portion of the cam member 20 andfixed to the connector housing so as to retain one end of the spring 21relative to the connector housing. As a result, the ferrule 12, theferrule holder 16 and the cam member 20 are biased forwardly, yetpermitted to piston rearwardly relative to the connector housing 19.

As illustrated by the horizontal directional arrow in FIG. 1, a fieldoptical fiber 15 may be inserted into the rear end of the ferrule holder15 opposite the ferrule 12 and the stub optical fiber 14. Although notrequired, the mechanical splice connector 10 may be provided with ameans, for example a lead-in tube 24 (FIG. 4), for guiding the fieldoptical fiber 15 into the ferrule holder 16 and between the splicecomponents 17, 18 in general alignment with the stub optical fiber 14.Preferably, at least one of the splice components 17, 18 has a grooveformed therein for receiving the stub optical fiber 14 and the fieldoptical fiber 15. As shown herein, the lower splice component 18 isprovided with a lengthwise V-shaped groove for receiving and guiding thestub optical fiber 14 and the field optical fiber 15 into finealignment. Typically, the field optical fiber 15 is coated ortight-buffered with a buffer 25 that is stripped back to expose apredetermined length of the end of the field optical fiber. Themechanical splice connector 10 may be further provided with a crimp tubeor other strain relief mechanism (not shown) for retaining and strainrelieving the buffer 25 of the field optical fiber 15. With the buffer25 removed, the field optical fiber 15 can be inserted and advanced intothe rear of the mechanical splice connector 10 between the splicecomponents 17, 18 until the end portion of the field optical fiber 15makes physical contact with the end portion of the stub optical fiber14. The cam member 20 is actuated by moving or rotating the cam member20 relative to the ferrule holder 16 about the longitudinal axis of theconnector 10, to engage the keel on the splice component 18 and therebyforce the lower splice component 18 in the direction of the upper splicecomponent 17. Movement of the lower splice component 18 causes the endportion of the stub optical fiber 14 and the end portion of the fieldoptical fiber 15 to seat within the V-shaped groove formed in the lowersplice component 13, thereby aligning and simultaneously securing thefield optical fiber 15 relative to the stub optical fiber 14 between thesplice components. Accordingly, the field optical fiber 15 is opticallycoupled to the stub optical fiber 14, Further, as used herein, theportion of the connector where the optical coupling results is referredto as a “termination area.” In other embodiments, the field opticalfiber 15 or another optical fiber may be inserted into the ferruledirectly, and attached thereto as disclosed herein, in place of the stubfiber 14.

Generally, it should be understood that the adhesive compositionsdescribed herein may have application in adhering an optical fiber withany part of an optical connector, and are not limited to the adhesion ofa stub optical fiber to the inner wall of the ferrule. For example, theadhesive compositions described herein may be used to bond any part ofan optical connector to any optical fiber connected thereto, includingthe stub optical fiber and field optical fiber.

Also described herein are ferrule adhesion systems for use in an opticalconnector for terminating an optical fiber. The ferrule adhesion systemmay comprise a ferrule 12 comprising a fiber-receiving passage 30defining an inner surface and an adhesive composition 40 disposed withinthe ferrule 12 and in contact with the inner surface of the ferrule 12.Various embodiments of the adhesive composition 40 of the ferruleadhesion systems are described in detail herein. Such an adhesion systemmay contain the adhesive composition for a long period of time beforeheating to bond the fiber within the ferrule, such as 8 hours, 16 hours,1 day, 1 week, 1 month, 6 months, 1 year, or even several years. Forexample, the adhesive composition 40 may be in a solid powder form, suchas packed within the fiber-receiving passage 30 prior to being heated orotherwise activated and/or cured (e.g., via chemical catalyzing).Alternatively, the adhesive composition may be in a molded solid form inthe fiber-receiving passage 30 and then may be heated prior to theinsertion of the optical fiber.

Generally, methods for securing stub optical fibers to ferules ofoptical connectors 10 are disclosed herein. The method may generallycomprise the steps of supplying a ferrule adhesion system, heating theadhesive composition to a temperature sufficient to melt the adhesivecomposition, inserting the optical fiber into the fiber-receivingpassage of the ferrule and into contact with the adhesive composition,and cooling the adhesive composition.

The ferrule with an adhesive composition disposed within may be heatedto melt the adhesive composition to allow for the optical fiber to slideinto the opening of the ferrule. The heating may be at an elevatedtemperature, such as to allow for cross linking or other chemicalreactions to occur within some embodiments of the adhesive composition.Heating may be performed by a laser (e.g., commercially-available,industrial CO₂ laser with at least 100 W capacity), or any other heatingprocess. The heating step may take less than about 15 seconds with alaser, such, as even less than 10 seconds, less than 8 seconds, or lessthan 6 seconds. The adhesive composition may then be allowed to cool byany process, such as by accelerated cooling or through simple cooling inan ambient atmosphere at or near room temperature. The cooled adhesivecomposition is set and may stably adhere the optical fiber to theferrule. In some embodiments, the ferrule and adhesive composition maysubstantially cool as to set the adhesive composition within 5 minutes,2 minutes, 1 minute, 30 seconds, or even 15 seconds in room temperatureair (25° C.) at sea level pressure and zero humidity.

Various embodiments of adhesive compositions will now be disclosedherein. As used herein, an “adhesive” is a substance capable of holdingmaterials together by surface attachment. In one embodiment, theadhesive composition may generally comprise a partially cross-linkedresin and a coupling agent. In some embodiments, there may be betweenabout 0.1 to about 10 parts by weight of the coupling agent per 100parts by weight of the partially cross-linked resin. In variousembodiments, there may be about 0.1, about 0.5, about 1, about 2, about4, about 6 about 8, or about 10 parts by weight of the coupling agentper 100 parts by weight of the partially cross-linked resin, or a rangebetween any combination of the above mentioned weight ratios.

As used herein, a “thermoplastic resin” is a material that comprises apolymeric material that will repeatedly soften when heated and hardenwhen cooled, without polymer chains cross-linking. For example, athermoplastic resin may be repeatedly made soft and hard through heatingand cooling cycles. As used herein, “cross-linking” or “cross-linked”refers to the chemical bonding that connects a polymer chain to anadjacent polymer chain, and “cross-linkable” describes a chemicalspecies that becomes at least partially cross-linked when sufficientheat is applied. As used herein, “partially cross-linking” or “partiallycross-linked” refers to chemical bonding that connects a polymer chainto an adjacent polymer chain where not all adjacent chains are bonded,in contrast to thermoplastic and thermoset resins; and “partiallycross-linkable” describes a chemical species that becomes partiallycross-linked when sufficient heat is applied. It should be understoodthat when the terms “partially cross-linked” and “partiallycross-linkable” are used to describe polymers of adhesive compositionsdescribed herein, the same resin is being described at a specific timeof prior to cross linking or following cross-linking, For example, theresin is described as partially cross-linkable when it is packed intothe ferrule and has not yet been heated to be partially cross-linked.Following heating, the resin may be partially cross-linked. In anotherembodiment, the resin may be cross-linked prior to the heating stepimmediately prior to the insertion of the optical fiber, such as if theadhesive composition is injection molded prior to being placed into theferrule. However, an injection molded adhesive composition may still bedescribed as partially cross-linkable, as cross-linking may take placein the heating step immediately prior to optical fiber insertion. Itshould further be understood that when the adhesive composition isdescribed herein, if the adhesive composition is said to comprise apartially cross-linked resin then that is equivalent to saying that theadhesive composition comprises a partially cross-linkable resin prior tothat cross linking step. While cross-linking may provide a permanence tofix structures securely together during connector assembly andthermoplastic resins may allow for materials to flow in a controlledmanner for ferrule manufacturing, partially cross-linking materials mayuniquely and synergistically have such advantages of both types ofmaterials.

In one embodiment, the adhesive composition may comprise the propertythat at least about 5% by weight of the resin is cross-linked orcross-linkable and at least about 5% by weight of the resin is notcross-linked or cross-linkable. In another embodiment, the adhesivecomposition may comprise the property that at least about 10% by weightof the resin is cross-linked or cross-linkable and at least about 10% byweight of the resin is not cross-linked or cross-linkable, In anotherembodiment, the adhesive composition may comprise the property that atleast about 20% by weight of the resin is cross-linked or cross-linkableand at least about 20% by weight of the resin is not cross-linked orcross-linkable.

In some embodiments, the partially cross-linked resin materials may havea melting point at temperatures of at least about 250° C., 270°, or 290°C. In some embodiments, the partially cross-linked resin materials maycrosslink in the presence of air at temperatures of at least about 300°C, 325° C, or 350° C. Additionally, the partially cross-linked resin maybe capable of bonding in less than about 5 minutes, 3 minutes, 1 minute,30 seconds, or even 15 seconds. In contemplated embodiments, thepartially cross-linked resin does not require mixing, does not de-air,and/or does not have potlife issues. In one embodiment, the adhesivecomposition may comprise one or more partially cross-linked resins suchas, but not limited to, a partially cross-linked poly(phenylenesulfide).

In other embodiments, the adhesive composition may comprise one or morepartially or non-partially cross-linked resins such as, but not limitedto, a poly(phenylene oxide), a polyamide-imide, a liquid crystalpolymer, a polyether ether ketone, a cyclic olefin copolymer, orcombinations thereof. For example, the poly(phenylene sulfide) maycomprise, but is not limited to, Ryton® V-1, available from ChevronPhillips Chemical Company LLC of The Woodlands, Tex., or Fortran® 0205P4Fortron® 0203P6, available from Ticona GmbH of Frankfurt, Germany. Thepoly(phenylene oxide) may comprise, but is not limited to, Sabic SA-102,available from SABIC of Riyadh, Saudi Arabia. The liquid crystal polymermay comprise Veectra® A950 VF3001, available from Ticona of Florence,Ky. The polyether ether ketone may comprise Ketaspire' KT-851, availablefrom Solvay S.A. of Brussels, Belgium. The cyclic olefin copolymer maycomprise TOPAS® 50131-10 from Topas Advanced Polymers.

The coupling agent may comprise a wide variety of one or more suitablecoupling agents. In one embodiment, the coupling agent may comprise anepoxy, amino, or mercapto-functional silane. The silane group on thecoupling agent may comprise an alkoxysilane, an oxime silane, an acetoxysilane. Alternatively, or in combination with the above mentioned silanecoupling agent, the coupling agent may comprise a zirconate, a titanate,or combinations thereof. In one embodiment, the coupling agent maycomprise glycidoxypropyl trimethoxysilane, such asgamma-glycidoxypropyltrimethoxy silane. For example, the coupling agentsmay comprise Silquest® A-187, Silquest® A-1100, available from CromptonCorp. of Middlebury, Conn., or Ken-React® KR55, available from KenrichPetrochemicals, inc. of Bayonne, N.J.

The combination of a coupling agent and a partially cross-linked resinray produce enhanced adhesion strength, Without being bound by theory,it is believed that the coupling agent may provide a chemical couplingbetween the inorganic surface of the optical fiber and/or the ferrule,and the polymer matrix of the adhesive. After cooling, the partiallycross-linked resin, which may have no functional groups which can reactwith inorganic surfaces, may be covalently bonded to one or both of theoptical fiber or ferrule by the coupling agent. The coupling agent maycomprise functional groups specifically capable of bonding covalently toinorganic materials, and groups specifically capable of reacting withorganic functional groups, The organic functional group on the couplingagent can comprise epoxy amino, mercapto, acrylic, ester or any otherorganic functional group. In one embodiment, the functional group on thecoupling agent which reacts with the inorganic materials analkoxysilane. Other possible groups include an oxime- or acetoxy-silane.In addition to silane coupling agents, zirconates and titanates havealso been shown to have such coupling capabilities.

The adhesive composition described herein may further comprise at leastone thermoset resin, A wide variety of thermoset resin materials may beused as a component of the adhesive composition. As used herein, a“thermoset resin” is a material that comprises at least one polymericmaterial that will undergo or has undergone a chemical reaction by theaction of heat, catalysts, ultraviolet light leading to a relativelyinfusible state. Examples of suitable thermoset resins may include, butis not limited to, epoxy resins, such as Bisphenol A based epoxy orepoxy novolacs. In one embodiment, there may be between about 1 to about85 parts by weight of the thermoset resin per 100 parts by weight of thepartially cross-linked resin. In various embodiments, there may be about1, about 5, about 10, about 30, about 50, about 70, about 80, or about85 parts by weight of the thermoset resin per 100 parts by weight of thepartially cross-linked resin, or a range between any combination of theabove mentioned weight ratios.

The combination of a thermoset resin and a partially cross-linked resinmay produce enhanced adhesion strength. Without being bound by theory,it is believed that after cure at temperature above 300° C., the,adhesive may form a uniform system of thermoplastics and a cross linkednetwork structures throughout the matrix. The cross-link structure maybe formed not only by the thermoset but also between thermoplastics andthermoset. For example, the partially cross-linked thermoplastic resincould react with the thermoset resin at elevated temperatures by aphenol group at the end of the polymer chain. The formed networkstructure may improve integrity of the adhesives and corresponding fiberoptic connectors to resist environmental aging and creep under shearstress and promote bonding strength on the substrates.

In one embodiment, the adhesive composition may further comprise acuring, agent. Without being bound by theory, it is believed that thecuring agent may aid in curing the thermoset resin, such as an epoxyresin, if the adhesive composition comprises a thermoset resin, and/ormay aid in curing the coupling agent. For example, the curing agent mayreact with the epoxy groups of a coupling agent and/or thermoset resin.The curing agent may comprise one or more curing agents available, suchas, but not limited to, an anhydride curative, an amide curative, anaromatic amine curative, a dianhydride, a mono acid anhydride, aguanidine compound, an amine curative, or combinations thereof. Forexample, the curing agent may comprise a dicyandiamide, pyromelliticdianhydride, a dodecylsuccinic anhydride, a urone, a urea, a melamine, adicyandiamide, or combinations thereof. In one embodiment, the adhesivecomposition further comprises between about 0.2 to about 50 parts byweight of a curing agent per 100 parts by weight of the coupling agent.In various embodiments, there may be about 0.2, about 0.5, about 1,about 5, about 10, about 20, about 30, about 40, or about 50 parts byweight of the curing agent per 100 parts by weight of the couplingagent, or a range between any combination of the above mentioned weightratios. In another embodiment, the adhesive composition furthercomprises between about 0.2 to about 50 parts by weight of a curingagent per 100 parts by weight of the thermoset resin. In variousembodiments, there may be about 0.2, about 0.5, about 1, about 5, about10, about 20, about 30, about 40, or about 50 parts by weight of thecuring agent per 100 parts by weight of the thermoset resin, or a rangebetween any combination of the above mentioned weight ratios. In yetanother embodiment, the adhesive composition further comprises betweenabout 0.2 to about 100 parts by weight of a curing agent per 100 partsby weight of the sum of the weight of the thermoset resin and the weightof the coupling agent. In various embodiments, there may be about 0.2,about 0.5, about 1, about 5, about 10, about 30, about 50, about 70,about 90, or about 100 parts by weight of the curing agent per 100 partsby weight of the sum of the weight of the thermoset resin and the weightof the coupling agent, or a range between any combination of the abovementioned weight ratios.

In one embodiment, the adhesive composition may further comprise one ormore filler materials. In one embodiment, the filler material is amineral composition, such as at least one pyrophosphate of a metal Forexample, the metal may comprise cobalt or magnesium, such that thefiller material is magnesium pyrophosphate, cobalt pyrophosphate, orcombinations thereof. In one embodiment, the adhesive compositionfurther comprises between about 0.5 to about 85 parts by weight of afiller material per 100 parts by weight of the partially cross-linkedresin. In various embodiments, there may be about 0.5, about 1, about 5,about 10, about 30, about 50, about 70, about 80, or about 85 parts byweight of the filler material per 100 parts by weight of the thermosetresin, or a range between any combination of the above mentioned weightratios.

In one embodiment, the filler material may comprise a material with anegative coefficient of thermal expansion. As used herein, a materialwith a negative coefficient of thermal expansion refers to a materialthat goes through a phase inversion with the accompanying decrease involume at a temperature near to, for example within about 50° C., about30° C., about 20° C., or about 10° C., of the glass transitiontemperature of the partially cross-linked resin, Without being bound bytheory, it is believed that the inclusion of a material with a negativecoefficient of thermal expansion may aid in maintaining the density, andtherefore the volume, of the adhesive composition when it is heated,such that it does not expand as to apply excessive pressure to theferrule, in some circumstances causing the ferrule to crack or rupture.

It should be understood that various components of the adhesivecomposition embodiments disclosed herein may be combined in anycombination in any ratio disclosed herein. Such various componentsinclude partially cross-linked resins, coupling agents, thermosetresins, curing agents, and filler materials. Furthermore, whiledesirable properties of the adhesive composition may be caused by thecombination of only two or more of the various components, anycombination of the components is contemplated herein. It should furtherbe understood that where a component of the adhesive composition isreferenced, it may be an optional component is some embodiments, and isnot required to be in the adhesive composition is all embodiments.

For example, in one preferred embodiment, the adhesive composition maycomprise a partially cross-linked resin, a coupling agent, curing agent,and partially cross-linked resin, The adhesive composition may comprisebetween about 0.1 to about 10 parts by weight of the coupling agent per100 parts by weight of the partially cross-linked resin, between about0.2 to about 5 parts by weight of a curing agent per 100 parts by weightof the partially cross-linked resin, and between about 0.5 to about 85parts by weight of a filler material per 100 parts by weight of thepartially cross-linked resin.

In one embodiment, the adhesive composition is prepared as a solidpowder. At least some of the various components of the adhesivecomposition may be solid, and may be ground into a powder, such as anyor all of the partially cross-linked resin, the thermoset resin, thecuring agent, and/or the filler material. The solid powder materials maybe thoroughly mixed. In one embodiment, the coupling agent may be aliquid. However, the fraction of coupling agent in the blend isrelatively small so the coupling agent may be combined with one of thesolid components of the adhesive composition and the resulting blend maya free-flowing powder. For example, in one embodiment, the couplingagent may be pre-reacted with the partially cross-linkable resin powdersin an organic solvent under refluxing conditions. After removal of thesolvent, the treated powder remains. Under the conditions of refluxingsolvent, some of the coupling agent may have become permanently bondedto the polymer.

In some embodiments, the adhesive composition may be in the form of asolid powder and may be directly packed into the fiber receiving passageof the ferrule (shown in FIG. 1 as the space occupied by the stuboptical fiber 14 within the ferrule 12). In some other embodiments,particularly when the adhesive composition does not comprise a thermosetresin, the adhesive composition may be extruded or injection molded intopreforms as solid material following an initial heating step. Adhesivecompositions comprising a thermoset resin may not be capable of beingextruded or injection molded into preforms because they may not becapable of being heated again while within the ferrule to receive andbond the stub optical fiber. As such, a partially cross-linking resinmay provide advantages of both thermoset and thermoplastic resins.

EXAMPLE

An adhesive composition was prepared with poly(phenylene sulfide)(Ryton® V-1) and Gamma-Glycidoxypropyltrimethoxy silane, an epoxysilane, using 1.5 parts by weight of Gamma-Glycidoxypropyltrimethoxysilane per 100 parts by weight of poly(phenylene sulfide). The couplingagent was pre-reacted for 8 hours with the partially cross-linkableresin powders in a mixture containing 99% organic solvent and 1%Gamma-Glycidoxypropyltrimethoxy silane under refluxing conditions. Afiller material of pyromellitic dianhydride was also mixed into theadhesion composition at a weight ratio of 03 per 100 parts ofpoly(phenylene sulfide), The resultant adhesive composition was a freeflowing powder that was thereafter packed into the fiber receivingpassage of a ferrule. The ferrule and adhesive composition were thenheated with a laser until the adhesive composition melted, and anoptical fiber was inserted into the fiber receiving passage. The ferruleand adhesive composition were then cooled through exposure to ambientconditions.

Adhesion strength was analyzed with a Chatillon tensile test set. Thefiber was wrapped around a mandrel then pull vertically until the fiberbroke or the bond failed. The tensile peak was recorded. The ferrulebonded to the optical fiber was also tested under exposure to 2 day and7 day environmental conditions. A control group was also used that wasnot exposed the environmental conditions. The samples that were agedunder environmental conditions went through an environmental cyclingregime consisting of a 6 hour cycle that consisted of 2 hours at about22° C., 2 hours of temperature moving linearly from about 22° C. toabout −40° C., 2 hours at about -40° C., 2 hours of temperature movinglinearly from about −40° C. to about 85° C., 2 hours at about 85° C. andabout 90% humidity, and 2 hours of temperature moving linearly fromabout 85° C. to about 22° C. 2 day environmental tests samples wentthrough 8 cycles and 7 day environmental test samples went through 28cycles. The adhesion strength data is shown below for the adhesivecomposition described above as well as other various comparativesamples:

Environmental Peak Tensile Adhesive Composition Cycling Strength (lbf)100% Locite epoxy none 4.0 100% poly(phenylene sulfide) none 3.1 100%poly(phenylene sulfide) 2 days 2.5 poly(phenylene sulfide), none 6.5gamma-glycidoxypropyltrimethoxy silane, pyromellitic dianhydride(100:1.5:.0.5 wt. ratio) poly(phenylene sulfide), 2 days 5.0gamma-glycidoxypropyltrimethoxy silane, pyromellitic dianhydride(100:1.5:.0.5 wt. ratio) poly(phenylene sulfide), 7 days 4.5gamma-glycidoxypropyltrimethoxy silane, pyromellitic dianhydride(100:1.5:.0.5 wt. ratio)

In one embodiment, the adhesive composition may generally comprise apartially cross-linked resin and a thermoset resin, in one embodiment,there may be between about 1 to about 85 parts by weight of thethermoset resin per 100 parts by weight of the partially cross-linkedresin. in various embodiments, there may be about 1, about 5, about 10,about 30, about 50, about 70, about 80, or about 85 parts by weight ofthe thermoset resin per 100 parts by weight of the partiallycross-linked resin, or a range between any combination of the abovementioned weight ratios,

A wide variety of thermoset resin materials may be used as a componentof the adhesive composition, As used herein, a “thermoset resin” is amaterial that comprises at least one polymeric material that willundergo or has undergone a chemical reaction by the action of heat,catalysts, ultraviolet light, etc., leading to a relatively infusiblestate. Examples of suitable thermoset resins may include, but is notlimited to, epoxy resins, such as Bisphenol A based epoxy or epoxynovolacs.

The combination of a thermoset resin and a partially cross-linked resinmay produce enhanced adhesion strength. Without being bound by theory,it is believed t hat after cure at temperature above 300° C., theadhesive may form a uniform system of partially cross-linked resins anda cross linked network structure throughout the matrix. The cross-linkstructure may be formed not only by the thermoset but also betweenpartially cross-linked resins and thermoset resins. For example, thepartially cross-linked resin could react with the thermoset resin atelevated temperatures by a phenol group at the end of the polymer chain.The formed network structure may improve integrity of the adhesives andcorresponding fiber optic connectors to resist environmental aging andcreep under shear stress and promote bonding strength on the substrates,

The adhesive composition described herein may further comprise at leastone coupling agent. The coupling agent may comprise a wide variety ofone or more suitable coupling agents. In one embodiment, the couplingagent may comprise an epoxy, amino, or mercapto-functional silane. Thesilane group on the coupling agent may comprise an alkoxysilane, anoxime shine, an acetoxy silane. Alternatively, or in combination withthe above mentioned silane coupling agent, the coupling agent maycomprise a zirconate, a titanate, a silane with an epoxy ring on one endand trimethoxy functional group at the other end, or combinationsthereof. In one embodiment, the coupling agent may compriseglycidoxypropyi trirnethoxysilane, such asgamma-glycidoxypropyltrimethoxy silane, For example, the coupling agentsmay comprise Silquese A-187, Silquest A-1100, available from CromptonCorp, of Middlebury, Conn., or Ken-Reacts KR55, available from KenrichPetrochemicals, Inc. of Bayonne, N.J. In some embodiments, there may bebetween about 0.1 to about 10 parts by weight of the coupling agent per100 parts by weight of the partially cross-linked resin. in variousembodiments, there may be about OA, about 03, about 1, about 2, about 4,about 6, about 8, or about 10 parts by weight of the coupling agent per100 parts by weight of the partially cross-linked resin, or a rangebetween any combination of the above mentioned weight ratios.

Some or all of the following may be identically or inherently disclosedabove and/or in the Figures.

In one embodiment, the adhesive composition may comprise the partiallycross-linked resin in an amount greater than or equal to about 30% byweight of the adhesive composition. In other embodiments, the adhesivecomposition may comprise the partially cross-linked resin in an amountgreater than or equal to about 40% by weight of the adhesivecomposition, greater than or equal to about 50% by weight of theadhesive composition, greater than or equal to about 60% by weight ofthe adhesive composition, greater than or equal to about 70% by weight,greater than or equal to about 80% by weight of the adhesivecomposition, greater than or equal to about 90% by weight of theadhesive composition, greater than or equal to about 95% by weight ofthe adhesive composition, or even greater than or equal to about 98% byweight of the adhesive composition.

In one embodiment, the partially cross-linked resin may comprise two ormore chemical species. in one embodiment, the partially cross-linkedresin may be one chemical species, such as, for example, apoly(phenylene oxide), a polyamide-imide, a liquid crystal polymer, apolyether ether ketone, a cyclic olefin copolymer, or combinationsthereof. in one embodiment, the adhesive composition may comprise onechemical species that is a partially cross-linked resin in an amountgreater than or equal to about 30% by weight of the adhesivecomposition. In other embodiments, the adhesive composition may compriseone chemical species that is a partially cross-linked resin in an amountgreater than or equal to about 40% by weight of the adhesivecomposition, greater than or equal to about 50% by weight of theadhesive composition, greater than or equal to about 60% by weight ofthe adhesive composition, greater than or equal to about 70% by weightof the adhesive composition, greater than or equal to about 80% byweight of the adhesive composition, greater than or equal to about 90%by weight of the adhesive composition, greater than or equal to about95% by weight of the adhesive composition, or even greater than or equalto about 98% by weight of the adhesive composition.

In one embodiment, the partially cross-linked resin may comprisepoly(phenylene sulfide). In one embodiment, the adhesive composition maycomprise poly(phenylene sulfide) in an amount greater than or equal toabout 30% by weight of the adhesive composition. In other embodiments,the adhesive composition may comprise poly(phenylene sulfide) in anamount greater than or equal to about 40% by weight of the adhesivecomposition, greater than or equal to about 50% by weight of theadhesive composition, greater than or equal to about 60% by weight ofthe adhesive composition, greater than or equal to about 70% by weightof the adhesive composition, greater than or equal to about 80% byweight of the adhesive composition, greater than or equal to about 90%by weight of the adhesive composition, greater than or equal to about95% by weight of the adhesive composition, or even greater than or equalto about 98% by weight of the adhesive composition.

In one embodiment, the adhesive composition may comprise the couplingagent in an amount of less than or equal to about 30% and greater thanabout 0.1% by weight of the adhesive composition. In other embodiments,the adhesive composition may comprise the coupling agent in an amountless than or equal to about 20% and greater than about 0.1% by weight ofthe adhesive composition, less than or equal to about 10% by weight ofthe adhesive composition, less than or equal to about 8% and greaterthan about 0.1% by weight of the adhesive composition, less than orequal to about 5% and greater than about 0.1% by weight of the adhesivecomposition, greater than or equal to about 4% and greater than about0.1% by weight of the adhesive composition, less than or equal to about2% by weight of the adhesive composition, less than or equal to about 1%and greater than about 0.1% by weight of the adhesive composition, oreven less than or equal to about 0.5% and greater than about 0.1% byweight of the adhesive composition. In other embodiments, the adhesivecomposition may comprise the coupling agent in an amount between about0.5% and about 20% by weight of the adhesive composition, between about0.5% and about 10% by weight of the adhesive composition, between about6% and about 1% by weight of the adhesive composition, between about 4%and about 1% by weight of the adhesive composition, or between about 3%and about 1% by weight of the adhesive composition.

In one embodiment, the partially cross-linked resin may have a meltingpoint of between about 200° C. and about 350° C. In other embodiments,the partially cross-linked resin may have a melting point of betweenabout 225° C. and about 325° C., between about 250° C. and about 300°C., between about 270° C. and about 295° C. , or between about 275° C.and about 280° C. , In one embodiment, the partially cross-linked resinmay have a melting point of about 278° C.

In one embodiment, the partially cross-linked resin may be a polymer. Inone embodiment, the coupling agent may provide chemical coupling betweenthe polymer and at least one of the optical fiber and the ferrule. Asused herein, chemical coupling refers to any chemical bonding,including, but not limited to, one or more of covalent bonding, ionicbonding, or intermolecular bonding such as dipole-dipole interactions,hydrogen bonding, and London dispersion bonding. In one embodiment, thepartially cross-linked resin may be poly(phenylene sulfide). In oneembodiment, the coupling agent may be a silane coupling agent, wherebythe adhesive composition comprises between)out 0.1 to about 10 parts byweight of the silane coupling agent per 100 parts of the poly(phenylenesulfide). In one embodiment, the partially cross-linked re may be onechemical species. The one chemical species may be selected from thegroup consisting of a poly(phenylene sulfide), a poly(phyenylene oxide),a polyamide-imide, a liquid crystal polymer, a polyether ether ketone,and a cyclic olefin copolymer.

In one embodiment, an optical connector may be used for terminating anoptical fiber. The optical connector may comprise a ferrule, wherein theferrule comprises a fiber-receiving passage defining an inner surface.The optical connector may also comprise an optical fiber, extendingthrough the fiber-receiving passage. The optical connector may alsocomprise an adhesive composition, wherein the adhesive composition maybe disposed within the fiber-receiving passage of the ferrule and may bein contact with the inner surface of the ferrule and the optical fiber,wherein the adhesive composition comprises a partially cross-linkedresin, and wherein the adhesive composition comprises the partiallycross-linked resin in an amount greater than or equal to about 30% byweight of the adhesive composition.

In one embodiment, a ferrule adhesion system may be used in an opticalconnector for terminating an optical fiber. The ferrule adhesion systemmay comprise a ferrule comprising a fiber-receiving passage defining aninner surface. The ferrule adhesion system may also comprise an adhesivecomposition The adhesive composition may be disposed in thefiber-receiving passage of the ferrule and in contact with the innersurface of the ferrule. The adhesive composition may comprise apartially cross-linkable resin in an amount greater than or equal toabout 50% by weight of the adhesive composition. The adhesivecomposition may be a solid material without securing an optical fiber inthe fiber-receiving passage of the ferrule.

In one embodiment, an optical fiber may be secured to a ferrule. Thesecuring method may comprise supplying a ferrule adhesion system, theferrule adhesion system comprising the ferrule and an adhesivecomposition. The securing method may also comprise heating the adhesivecomposition to a temperature sufficient to melt the adhesivecomposition. The securing method may also comprise inserting the opticalfiber into a fiber-receiving passage defining an inner surface of theferrule and into contact with the adhesive composition. The securingmethod may also comprise cooling the adhesive composition. The adhesivecomposition may be disposed within the ferrule and in contact with theinner surface of the ferrule. The adhesive composition may comprise apartially cross-linkable resin prior to the heating step. The adhesivecomposition may comprise a partially cross-linked resin in an amountgreater than or equal to about 50% by weight of the adhesive compositionfollowing the cooling step.

In one embodiment, an optical connector may be used for terminating anoptical fiber. The optical connector may comprise a ferrule, wherein theferrule may comprise a fiber-receiving passage defining an innersurface. The optical connector may also comprise an optical fiber,extending through the fiber-receiving passage, the optical connector mayalso comprise an adhesive composition, wherein the adhesive compositionmay be disposed within the fiber-receiving passage of the ferrule andmay be in contact with the inner surface of the ferrule and the opticalfiber. The adhesive composition may comprise a partially cross-linkedresin that may be a polymer. The adhesive composition may also comprisea coupling agent that provides chemical coupling between the polymer andat least one of the optical fiber and the ferrule, wherein the adhesivecomposition may comprise between about 0.1 to about 10 parts by weightof the coupling agent per 100 parts by weight of the partiallycross-linked resin. In one embodiment, the partially cross-linked resinmay be one chemical species. In one embodiment, the one chemical speciesmay be selected from the group consisting of a poly(phenylene sulfide),a poly(phyenylene oxide), a polyamide-imide, a liquid crystal polymer, apolyether ether ketone, and a cyclic olefin copolymer. In oneembodiment, the partially cross-linked resin may be poly(phenylenesulfide). In one embodiment, the coupling agent may be a silane couplingagent, whereby the adhesive composition may comprise between about 0.1to about 10 parts by weight of the silane coupling agent per 100 partsof the poly(phenylene sulfide).

In one embodiment, a ferrule adhesion system may be used in an opticalconnector for terminating an optical fiber, The ferrule adhesion systemmay comprise a ferrule comprising a fiber-receiving passage defining aninner surface. The ferrule adhesion system may also comprise an adhesivecomposition, The adhesive composition may be disposed in thefiber-receiving passage of the ferrule and in contact with the innersurface of the ferrule. The adhesive composition may comprise apartially cross-linkable resin, wherein the partially cross-linkableresin may comprise poly(phenylene sulfide). The adhesive composition maybe a solid powder material packed into the fiber-receiving passage ofthe ferrule.

In one embodiment, an optical fiber may be secured to a ferrule. Thesecuring method may comprise supplying a ferrule adhesion system, theferrule adhesion system comprising the ferrule and an adhesivecomposition. The securing method may also comprise heating the adhesivecomposition to a temperature sufficient to melt the adhesivecomposition. The securing method may also comprise inserting the opticalfiber into a fiber-receiving passage defining an inner surface of theferrule and into contact with the adhesive composition. The securingmethod may also comprise cooling the adhesive composition.

The adhesive composition may be disposed within the ferrule and incontact with the inner surface of the ferrule. The adhesive compositionmay comprise a partially cross-linkable resin prior to the heating step.The adhesive composition may comprise, a partially cross-linked resinfollowing the cooling step. The partially cross-linked resin maycomprise poly(phenylene sulfide). The adhesive composition may be in asolid form prior to the heating step. The heating step may be performedby a laser of at least 100 W capacity and takes less than 15 secondsuntil the adhesive composition may be melted. The cooling step takesless than 5 minutes until the adhesive composition solidifies andpartially cross links to secure the optical fiber. In one embodiment,the coupling agent may be a silane coupling agent, whereby the adhesivecomposition may comprise between about 0.1 to about 10 parts by weightof the silane coupling agent per 100 parts of the poly(phenylenesulfide).

For the purposes of describing and defining the present disclosure it isnoted that the term “about” are utilized herein to represent theinherent degree of uncertainty that may be attributed to anyquantitative comparison, value, measurement, or other representation.The term “about” are also utilized herein to represent the degree bywhich a quantitative representation may vary fro a stated referencewithout resulting in a change in the basic function of the subjectmatter at issue.

It is noted that terms like “preferably,” “commonly,” and “typically,”when utilized herein, are not utilized to limit the scope of the claimsor to imply that certain features are critical, essential, or evenimportant to the structure or function of the claims. Rather, theseterms are merely intended to identify particular aspects of anembodiment of the present disclosure or to emphasize alternative oradditional features that may or may not be utilized in a particularembodiment of the present disclosure.

It is noted that one or more of the following claims utilize the term“wherein” as a transitional phrase. For the purposes of defining thepresent technology, it is noted that this term is introduced in theclaims as an open-ended transitional phrase that is used to introduce arecitation of a series of characteristics of the structure and should beinterpreted in like manner as the more commonly used open-ended preambleterm “comprising.”

It should be understood that any two quantitative values assigned to aproperty may constitute a range of that property, and all combinationsof ranges formed from all stated quantitative values of a given propertyare contemplated herein.

Having described the subject matter of the present disclosure in detailand by reference to specific embodiments thereof, it is noted that thevarious details disclosed herein should not be taken to imply that thesedetails relate to elements that are essential components of the variousembodiments described herein, even in cases where a particular elementis illustrated in each of the drawings that accompany the presentdescription. Rather, the claims appended hereto should be taken as thesole representation of the breadth of the present disclosure and thecorresponding scope of the various embodiments described herein.Further, it will be apparent that modifications and variations arepossible without departing from the scope of the appended claims.

What is claimed is:
 1. A method of securing an optical fiber to aferrule, comprising: disposing an adhesive composition in afiber-receiving passage of the ferrule to form a ferrule adhesionsystem, wherein the, adhesive composition in the ferrule adhesion systemcomprises a polymeric material in a solid form; assembling an opticalconnector with the ferrule adhesion system, wherein the opticalconnector includes a connector housing in which the ferrule is at leastpartially disposed; heating the ferrule in the optical connector to meltthe adhesive composition; and inserting the optical fiber into thefiber-receiving passage of the ferrule and into contact with theadhesive composition that has been melted, wherein the adhesivecomposition bonds the optical fiber to an inner surface of the ferruleupon cooling and solidifying.
 2. The method of claim 1, wherein theferrule is biased relative to the connector housing when the opticalconnector is assembled.
 3. The method of claim 1, wherein heating theferrule comprises heating the adhesive composition to a temperature ofat least about 300° C.
 4. The method of claim I, wherein heating theferrule comprises heating the adhesive composition to a temperature ofat least about 325° C.
 5. The method of claim 1, wherein: the polymericmaterial of the adhesive composition comprises a partiallycross-linkable resin prior to the heating step; and the polymericmaterial of the adhesive composition comprises a partially cross-linkedresin following the cooling step.
 6. The method of claim 1, wherein thepolymeric material of the adhesive composition comprises poly(phenylenesulfide).
 7. The method of claim 6, wherein the adhesive compositioncomprises the poly(phenylene sulfide) in an amount greater than or equalto about 30% by weight of the adhesive composition.
 8. The method ofclaim 7, wherein the adhesive composition comprises the poly(phenylenesulfide) in an amount greater than or equal to about 50% by weight ofthe adhesive composition.
 9. The method of claim 8, wherein the adhesivecomposition further comprises a coupling agent that is at least one ofthe following: an alkoxysilane, an oxime silane, an acetoxy silane, azirconate, a titanate, a silane with an epoxy ring on one end andtrimethoxy functional group at the other end, or combinations thereof.10. The method of claim 9, wherein the adhesive composition comprisesthe coupling agent in an amount between about 0.5% and about 20% byweight of the adhesive composition.
 11. The method of claim 1, whereinthe polymeric material of the adhesive composition comprisespoly(phenylene sulfide), and wherein the adhesive composition furthercomprises a coupling agent that chemically bonds the poly(phenylenesulfide) to an inorganic surface of at least one of the optical fiberand the ferrule following the cooling step.
 12. The method of claim 11,wherein the coupling agent that comprises at least one of the following:an alkoxysilane, an oxime silane, an acetoxy silane, a zirconate, atitanate, a silane with an epoxy ring on one end and trimethoxyfunctional group at the other end, or combinations thereof.
 13. Themethod of claim 1, wherein disposing the adhesive composition in thefiber-receiving passage further comprises: forming the adhesivecomposition in a powder form; and packing the powder form of theadhesive composition in the fiber-receiving passage.
 14. The method ofclaim 1, wherein disposing the adhesive composition in thefiber-receiving passage further comprises: forming the adhesivecomposition by extruding or injecting molding the adhesive composition asolid preform; and disposing the lid preform in the fiber-receivingpassage of the ferrule.
 15. A method of securing an optical fiber to aferrule, comprising: disposing an adhesive composition in afiber-receiving passage of the ferrule to form a ferrule adhesionsystem, wherein the adhesive composition comprises a polymeric materialin a solid form; storing the adhesive composition, in the solid form, inthe fiber-receiving passage of the ferrule for at least 8 hours; heatingthe ferrule to melt the adhesive composition after the storing step; andinserting the optical fiber into the fiber-receiving passage of theferrule and into contact with the adhesive composition that has beenmelted, wherein the adhesive composition bonds the optical fiber to aninner surface of the ferrule upon cooling and solidifying.
 16. Themethod of claim 15, wherein the adhesive composition is stored, in thesolid form, in the fiber-receiving passage of the ferrule for at least 1day.
 17. The method of claim 15, wherein heating the ferrule comprisesheating the adhesive composition to a temp nature of at least about 300°C.
 18. The method of claim 15, wherein the polymeric material of theadhesive composition comprises poly(phenylene sulfide).
 19. The methodof claim 18, wherein the adhesive composition comprises thepoly(phenylene sulfide) in an amount greater than or equal to about 50%by weight of the adhesive composition.
 20. The method of claim 19,wherein the adhesive composition further comprises a coupling agent thatis at least one of the following: an alkoxysilane, an oxime silane, anacetoxy silane, a zirconate, a titanate, a silane with an epoxy ring onone end and trimethoxy functional group at the other end, orcombinations thereof.
 21. The method of claim 20, wherein the adhesivecomposition comprises the coupling agent in an amount between about 0.5%and about 20% by weight of the adhesive composition.